When it comes to criminal cases, the evidence is incredibly important. For your defense, you want to disprove any evidence that is against you or try to show it violates the law in some way.
One common defense strategy is to prove there is an issue with the chain of custody. According to the National Center for Biotechnology Information, the chain of custody is the process of evidence documentation that shows exactly where it has been and who has been in control over it since law enforcement collected it.
The chain of custody is important because it validates the authenticity of the evidence. It also helps to show there is no contamination or manipulation of the evidence. In addition, properly following this procedure ensures that at any time someone can access the evidence if they need it. It prevents the loss of key evidence and keeps evidence records organized.
How it works
The process runs from the moment of collection at the crime scene until the prosecutor submit the evidence to the court. Upon collection, a person must put it in its own evidence bag or container. The person must then fill out documentation that identifies what it is, where it came from and other identifying details. The person collecting it must sign the document and provide contact information. The piece of evidence also receives a unique identifier, which is often an evidence number.
The evidence may only be in the possession of approved individuals. It will go immediately into evidence lockers. From there, only those who have permission may handle it or check it out of the evidence locker. Every interaction with the evidence requires a new record that provides information about who is accessing it and why.